Oh dear. They're wound up the 1.3CDTi to 90PS and put in in the Astra. It's rubbish engine in the Corsa, but 90PS out of a 1.3? That's going to melt in no time.
Still, the 1.3 unit is rated to 59mpg combined, 70mpg extra-urban.
I think I'd rather have a 80PS 1.7CDTi - less chance of it melting.